In many cases, they bring in people with talent to play each part of the song because a single player cannot play every part. If you want to make it big in internet marketing that's what you have to do. You gotta bring in a team who has skills in copywriting, bringing the traffic, running the ads etc.. because one person alone cannot manage to do everything. So my advice to you is just do what you love and if it doesn't work out you can always find other ways to get pay for what you love doing. And yes, it's better if you build a team.
That's my secret to you!

I didn't find the right solution from the Internet.

References: http://www.warriorforum.com/main-internet-marketing-discussion-forum/1288900-looking-reliable-niche.html?

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